The present invention relates to a method for reducing pests in an object or area by applying to the object or area a pest reducing effective amount of halogen substituted ethanol (e.g., 2-iodoethanol, 2-bromoethanol, or mixtures thereof). The pests may be, for example, fungi, insects, nematodes, bacteria, weeds, or mixtures thereof. The object or area may be, for example, soil, structures, agricultural commodities, plants, or mixtures thereof.
Methyl bromide is the chemical fumigant currently utilized to control fungi, nematodes, weeds, and insects in soil that is used for the production of high value agricultural crops such as strawberries, tomatoes, peppers, orchard crops, and vine crops. In 1992, methyl bromide was implicated as an ozone-depleting compound and subsequently the production levels of methyl bromide were frozen at the 1991 production levels. Methyl bromide is targeted for a 5-year phase-out beginning in the year 2000 and will be completely phased out by the year 2005 in accordance with the Montreal Protocol. The agricultural producing states most affected by this phase-out are Florida and California, which produce the majority of the tomatoes, peppers, strawberries, cut flowers, turf/sod, tobacco, melons, pineapples, orchard crops (e.g., peaches, citrus), and vine crops (e.g., grapes) grown in the United States. The aforementioned crops are the largest consumers of methyl bromide and other EPA registered fumigants for soil fumigation purposes. As methyl bromide is phased out, current crop yields are expected to be reduced by as much as forty percent due to increased pest and weed pressure in non-fumigated soil.
There currently exist only a few EPA registered and frequently studied methyl bromide alternatives: 1,3-dichloropropene, chloropicrin, metham sodium, dazomet, methyl iodide, propargyl bromide, sodium azide, and Enzone (EPA, Methyl Bromide Web Page); these are commonly applied as mixtures of two or more of the individual compounds in order to attempt to produce a more broad spectrum product. None of these EPA registered potential alternatives are drop-in replacements for methyl bromide based on performance or economics (drop-in replacement means that methodology, equipment, production system, etc., do not have to be changed significantly and that a comparable amount of material can be used for the same targets; i.e., the material is applied at nearly the same rate and with the same equipment as methyl bromide). All the potential replacement compounds, and even methyl bromide, have worker exposure and environmental/degradation issues.
Weed control in the absence of methyl bromide is considered to be one of the areas of greatest concern to growers. None of the methyl bromide alternatives provide adequate weed control, particularly of nutsedge and grass weeds. Nutsedge is considered to be the world's worst weed due to its status as a competitor with more crops in more countries than any other weed. Purple nutsedge grows well in almost any soil type and over a wide range of soil pH, moisture, and elevation. This weed is a significant problem in field crops, horticultural crops, and turf. It is one of the few weeds that can penetrate the plastic mulch that is used in the plant bed culture to suppress weed growth. Yields of some crops can be reduced by as much as 90% as a result of competition with this weed.
Nematode, plant pathogenic fungi, and insect control in the aforementioned crops are targets of methyl bromide and any alternative to methyl bromide. Control of all plant pathogens and pests is extremely important to the production of these crops and sustained economic viability.
One goal of our research project was to evaluate new compounds to determine their efficacy as replacements for methyl bromide.